1. Field of the Invention
The present invention relates to a method for producing a bung for a metal cask, in particular producing a bung for a relatively thin-walled cask, typically less than 2 mm thick. It relates to an improvement making it possible to simplify the production of such a bung and to reduce the cost price.
2. Description of the Related Art
A well known method for producing a bung for a metal cask, in particular a thin-walled cask, includes slipping onto the wall of the cask a collar which is prefabricated, relatively thick and internally threaded. Such a collar has a flat octagonally-shaped base. The wall of the cask is pierced and the metal is shaped around the piercing by making both an octagonal impression on the internal side and a cylindrical shaft extending outwards. The collar is inserted in the shaft in such a way that its octagonal base fits into the corresponding impression, with the insertion of a seal. The fixing of the collar is ensured by its rolled edge on the rim of the shaft.